Utility knife



FIG. 1 is a front elevational view of a utility knife showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left end view thereof;

FIG. 4 is a right end view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken line showing of the cutting blade is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a utility knife, as shown and described. 